??
The forcedTermination fault handler was able to do compensation. Why is
this a change?
No, the fact that the process does not have a termination handler is
deliberate since we do not have a notion of forced termination of a
process instance. I deliberately moved <terminate/> to <exit/> to make
that clear.
This proposal actually changes absolutely nothing semantically. It
simply changes syntax.
-----Original Message-----
From: Danny van der Rijn [mailto:dannyv@tibco.com]
Sent: Friday, September 24, 2004 8:31 AM
To: Satish Thatte
Cc: wsbpel@lists.oasis-open.org
Subject: Re: [wsbpel] Issue 135 - Proposal to vote
i don't like the idea of the default termination handler performing
compensation. this part is an addition, rather than a syntactic
substitution, and i think it falls on the wrong side of the meaning of
default.
also, i assume that the fact that a process doesn't have a termination
handler is an inadvertent omission?
danny
Satish Thatte wrote:
Overview:
The bpws:forcedTermination "fault" in the current specification is not
a normal fault. It is simply a way to permit interception of forced
termination by a scope to perform special handling to shut the scope
down in an orderly manner. The differences from a normal fault include
the inability to be caught by a catchAll handler, and the inability to
throw or rethrow any fault within the handler. It is thus proposed that
we eliminate the notion of a bpws:forcedTermination fault from the
specification and replace it with a notion of a special handler for
forced termination. A secondary part of the proposal is to replace the
<terminate/> activity with an <exit/> activity with identical semantics,
simply to avoid terminological confusion with the notion of forced
termination.
Detailed proposal:
In all the text of the specification, including section 5 and Appendix
A, eliminate the mention of bpws:forcedTermination and remove this token
from the bpws namespace.
In Sections 6.2 and 13
Replace the syntax
<scope variableAccessSerializable="yes|no" standard-attributes>
standard-elements
<variables>?
...
</variables>
<correlationSets>?
...
</correlationSets>
<faultHandlers>?
...
</faultHandlers>
<compensationHandler>?
...
</compensationHandler>
<eventHandlers>?
...
</eventHandlers>
activity
</scope>
with the syntax
<scope variableAccessSerializable="yes|no" standard-attributes>
standard-elements
<variables>?
...
</variables>
<correlationSets>?
...
</correlationSets>
<faultHandlers>?
...
</faultHandlers>
<compensationHandler>?
...
</compensationHandler>
<terminationHandler>?
...
</terminationHandler>
<eventHandlers>?
...
</eventHandlers>
activity
</scope>
In Section 13.4.2
Replace the text
Scopes provide the ability to control the semantics of forced
termination to some degree. When the activity being terminated is in
fact a scope, the behavior of the scope is interrupted and the fault
handler for the standard bpws:forcedTermination fault is run. Note that
this applies only if the scope is in normal processing mode. If the
scope has already experienced an internal fault and invoked a fault
handler, then as stated above, all other fault handlers including the
handler for bpws:forcedTermination are uninstalled, and the forced
termination has no effect. The already active fault handler is allowed
to complete.
The fault handler for the bpws:forcedTermination fault is designed like
other fault handlers, but this fault handler cannot rethrow any fault.
Even if an uncaught fault occurs during its behavior, it is not rethrown
to the next enclosing scope. This is because the enclosing scope has
already faulted, which is what is causing the forced termination of the
nested scope.
In other respects this is a normal fault handler. Its behavior begins
by implicitly (recursively) terminating all activities directly enclosed
within its associated scope that are currently active. It can invoke
compensate activities. And when it is missing, it is provided by using
the same implicit behavior that is used for all other implicit fault
handlers.
Note that forced termination of nested scopes occurs in innermost-first
order as a result of the rule (quoted above) that the behavior of any
fault handler begins by implicitly (recursively) terminating all
activities directly enclosed within its associated scope that are
currently active.
with the text
Scopes provide the ability to control the semantics of forced
termination to some degree. When the activity being terminated is in
fact a scope, the forced termination of a scope begins by terminating
all activities directly enclosed within its associated scope that are
currently active. Following this, the custom termination handler for
the scope, if present, is run. If the custom termination handler is
missing, the default termination handler performs compensation of all
successfully completed nested scopes in the same order as in the case of
a default fault handler.
Forced termination for a scope applies only if the scope is in normal
processing mode. If the scope has already experienced an internal fault
and invoked a fault handler, then the termination handler is
uninstalled, and the forced termination has no effect. The already
active fault handler is allowed to complete.
The termination handler for a scope is permitted to use the same range
of activities as a fault handler, including the <compensate/> activity.
However, a termination handler cannot throw any fault. Even if an
uncaught fault occurs during its behavior, it is not rethrown to the
next enclosing scope. This is because the enclosing scope has already
either faulted or is in the process of being terminated, which is what
is causing the forced termination of the nested scope.
Forced termination of nested scopes occurs in innermost-first order as
a result of the rule (stated above) that the termination handler is run
after terminating all activities (including scope activities) directly
enclosed within its associated scope that are currently active.
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